The invention relates to motor control circuits and in particular to an inductance switching circuit for increasing performance of a motor such as a variable reluctance motor.
Conventional variable reluctance motors operate with a plurality of coils (hereinafter “phase coils”), each coil corresponding to a phase of the motor and comprising a fixed number of turns of wire. The current in each of the phase coils is turned on and off each time a rotor pole passes a stator pole. Such a configuration creates a magneto-motive force which causes motion of the rotor relative to the stator.
A problem with conventional variable reluctance motors is the reduction in motor force (torque in rotary motors) delivered by such motors at high speeds, that is, speeds at which the current in the motor's phase coils cannot reach a desired value due to the inductance of the phase coils. There is a substantial and long felt need in the industry for motors that can operate effectively at higher speeds. It is therefore desirable to overcome the above-described limitations of conventional motor performance, including obtaining a higher motor force at higher speeds.